System and method for detecting structural integrity of a well casing

ABSTRACT

This disclosure relates to a system and method for detecting structural integrity of a well casing. The system may detect casing structural integrity events. The casing structural integrity events may include structural failures of the casing and/or potential structural failures of the casing. The well casing may be drilled and/or otherwise embedded into a geologic structure. The well casing may be subject to geologic forces generated by the geologic structure. Unplanned and/or unexpected forces and/or movement may pose a risk to the structural integrity of the casing. Forces and/or movement of sufficient magnitude may result in damage to and/or destruction of the casing. Damage to and/or destruction of the casing may cause a loss of the natural resources being extracted via the well associated with the well casing, contamination of areas surrounding the well, undesirable surface expression, and/or other negative effects.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional PatentApplication No. 61/777,553 filed Mar. 12, 2013, entitled “System AndMethod For Detecting Structural Integrity Of A Well Casing,” which isincorporated by reference herein.

FIELD OF THE DISCLOSURE

This disclosure relates to a system and method for detecting structuralintegrity of a well casing. The system may detect casing structuralintegrity events. The casing structural integrity events may includestructural failures of the casing and/or potential structural failuresof the casing related to the well tubing and/or other attached parts ofthe well structure.

BACKGROUND

Systems for sensing characteristics inside a well are known. Anelectrical connection to a well casing and a tubing string may power adown hole gauge and/or actuator. Current systems typically includegauges and/or actuators that monitor characteristics related to thenatural resources flowing through the well. The current systems do notdetect structural characteristics of the well casing.

SUMMARY

One aspect of the disclosure relates to a system configured to detectstructural integrity of a well casing in a well. The system may comprisea conductive well casing, conductive tubing, one or more sensors, one ormore processors, and/or other components.

The casing may be configured to surround the tubing. The tubing may beconfigured to communicate liquid and/or gas from an undergroundreservoir to above ground extraction equipment at or near a wellhead.The casing may be embedded in a geologic structure.

The one or more sensors may be configured to generate output signalsconveying information related to a structural integrity of the casing.The one or more sensors may include fluid level sensors, voltagesensors, acoustic sensors, pressure sensors, motion sensors, strainsensors, and/or other sensors. In some implementations, the one or moresensors may include one or more sensor types. In some implementations,the one or more sensors may include two or more sensor types.

In some implementations, at least one of the one or more sensors may beelectrically coupled with the tubing and the casing separately. At leastone of the one or more sensors may be located in the wellhead. The oneor more sensors may be located at one or more locations along the tubingwithin the casing. The one or more sensors may be located within thecasing at or near a tubing hanger between the wellhead and the tubing.The tubing hanger may be configured to suspend the tubing in the casing.

The one or more processors may be configured to detect casing structuralintegrity events based on the output signals. The one or more processorsmay be configured to generate casing structural integrity eventnotifications. The casing structural event notifications may correspondto the detected casing structural integrity events. The notificationsmay be generated for delivery to a user responsive to the detections.The casing structural integrity events may include structural failuresof the casing, potential structural failures of the casing, and/or otherevents. In some implementations, the one or more processors may beconfigured such that the casing structural integrity events are detectedresponsive to one or more forces acting on the casing. The one or moreforces may include a shear force, a tensile force, a compressive force,a torsional force, and/or other forces. The one or more forces may begenerated by the geologic structure surrounding the casing.

In some implementations, the one or more processors may be configured todetermine extraction parameters and to detect the casing structuralintegrity events based on the extraction parameters. The extractionparameters may include information indicating whether the well isoperating in a production phase or a pre-production phase, and/or otherinformation.

In some implementations, the one or more processors may be configured todetect the casing structural integrity events based on an algorithm. Theone or more processors may determine algorithm inputs based on theoutput signals. In some implementations, the one or more processors maybe configured to cluster the information conveyed by the output signalsand detect the casing structural integrity events based on theclustering. Clustering may comprise arranging the information conveyedby the output signals in a multidimensional space.

In some implementations, the one or more processors may be configured togenerate casing structural integrity scores based on the output signals.The one or more processors may be configured to detect the casingstructural integrity events based on the casing structural integrityscores.

In some implementations, the one or more processors may be configured todetermine one or more well parameters based on the output signals. Theone or more well parameters may include one or more of a fluid level, avoltage, an acoustic parameter, a pressure, a motion parameter, a strainlevel, and/or other parameters. The one or more processors may beconfigured to determine well parameter threshold levels. The one or moreprocessors may be configured to detect the casing structural integrityevents responsive to the well parameters breaching the well parameterthreshold levels.

Another aspect of the disclosure relates to method for detectingstructural integrity of a well casing in a well. The method may comprisesurrounding conductive well tubing with a conductive well casing. Thetubing may be configured to communicate liquid and/or gas from anunderground reservoir to above ground extraction equipment at awellhead. The casing may be embedded in a geologic structure.

The method may comprise generating output signals conveying informationrelated to a structural integrity of the casing. The method may includegenerating the output signals with one or more sensors. The one or moresensors may include fluid level sensors, voltage sensors, acousticsensors, pressure sensors, motion sensors, strain sensors, and/or othersensors. The one or more sensors may include one or more sensor types.The one or more sensors may include two or more sensor types.

In some implementations, the method may include electrically coupling atleast one of the one or more sensors with the tubing and the casingseparately. At least one of the one or more sensors may be located inthe wellhead. The one or more sensors may be located at one or morelocations along the tubing within the casing. The one or more sensorsmay be located within the casing at or near a tubing hanger between thewellhead and the tubing. The tubing hanger may be configured to suspendthe tubing in the casing.

The method may comprise detecting casing structural integrity eventsbased on the output signals. The casing structural integrity events maybe detected responsive to one or more forces acting on the casing. Theone or more forces may include a shear force, a tensile force, acompressive force, a torsional force, and/or other forces. The one ormore forces may be generated by the geologic structure surrounding thecasing.

The method may comprise generating casing structural integrity eventnotifications that correspond to the detected casing structuralintegrity events for delivery to a user responsive to the detections.The casing structural integrity events may include structural failuresof the casing, potential structural failures of the casing, and/or otherevents.

In some implementations, the method may include determining extractionparameters and detecting the casing structural integrity events based onthe extraction parameters. The extraction parameters may includeinformation indicating whether the well is operating in a productionphase or a pre-production phase.

The method may include detecting casing structural integrity eventsbased on an algorithm. The algorithm inputs may be determined based onthe output signals.

In some implementations, the method may include clustering theinformation conveyed by the output signals and detecting the casingstructural integrity events based on the clustering. Clustering maycomprise arranging the information conveyed by the output signals in amultidimensional space.

In some implementations, the method may include generating casingstructural integrity scores based on the output signals, and detectingcasing structural integrity events based on the casing structuralintegrity scores.

In some implementations, the method may include determining one or morewell parameters based on the output signals. The one or more wellparameters may include a fluid level, a voltage, an acoustic parameter,a pressure, a motion parameter, a strain level, and/or other parameters.The method may include determining well parameter threshold levels, anddetecting the casing structural integrity events responsive to the wellparameters breaching the well parameter threshold levels.

These and other features, and characteristics of the present technology,as well as the methods of operation and functions of the relatedelements of structure and the combination of parts and economies ofmanufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification,wherein like reference numerals designate corresponding parts in thevarious figures. It is to be expressly understood, however, that thedrawings are for the purpose of illustration and description only andare not intended as a definition of the limits of the invention. As usedin the specification and in the claims, the singular form of “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a system configured to detect structural integrity ofa well casing.

FIG. 2 illustrates an example configuration of multiple sensors.

FIG. 3 illustrates a natural resource field that includes multiplewells.

FIG. 4 illustrates a method for detecting structural integrity of a wellcasing.

DETAILED DESCRIPTION

FIG. 1 illustrates a system 10 configured to detect structural integrityof a well casing 12 in a well 8. Well 8 may be configured to extractminerals from an underground mineral reservoir. During mineralextraction, well 8 may be configured to communicate liquid and/or gasfrom the underground reservoir to above ground extraction equipment 16at or near a wellhead 28. Well 8 may be drilled and/or otherwiseembedded into a geologic structure. Well 8 may be subject to geologicforces generated by the geologic structure. Unplanned and/or unexpectedforces and/or movement may pose a risk to the structural integrity ofcasing 12. Forces and/or movement of sufficient magnitude may result indamage to and/or destruction of casing 12. Damage to and/or destructionof casing 12 may cause a loss of the natural resources being extractedvia well 8, contamination of areas surrounding well 8, undesirablesurface expression, and/or other negative effects.

System 10 may be configured to detect casing structural integrity eventsand generate casing structural integrity event notifications thatcorrespond to the detected casing structural integrity events. Thecasing structural integrity events may include structural failures ofcasing 12, potential structural failures of casing 12, and/or otherevents. In some implementations, system 10 may comprise casing 12, tube14, one or more sensors 18, one or more processors 20, user interface22, and/or other components.

Casing 12 may surround tube 14, sensors 18, and/or other components ofsystem 10. Casing 12 may line a borehole and provide structural supportfor well 8. Casing 12 may separate well 8 from the geologic structure.The geologic structure may include subsurface materials (e.g., rocks,dirt, etc.), water (e.g., in the case of a well in the ocean floor),and/or other environmental materials. Casing 12 may be made from aconductive material such as steel and/or other materials.

Tube 14 may be configured to communicate liquid and/or gas duringmineral extraction. Tube 14 may be configured to communicate liquidand/or gas from the underground reservoir to above ground extractionequipment 16 at or near wellhead 28. Tube 14 may be a tubing string. Thetubing string may include a series of coupled tubes. The series of tubesmay be coupled via threaded ends of each tube and/or other couplingmechanisms. In some implementations, the series of coupled tubes may bea series of coupled tubing joints. The joints may include, for example,a pup joint. Tube 14 may be made from electrically conductive materialssuch as steel and/or other electrically conductive materials.

As described above, tube 14 may be provided within casing 12. Providingtube 14 within casing 12 may create an inner annular space between theouter surface of tube 14 and casing 12. One or more centralizers may beconfigured to maintain tube 14 in the annular space to maintain aphysical separation between tube 14 and casing 12. The centralizers maycouple with the outside diameter of tube 14 via one or more couplingdevices. The coupling devices may include, for example, a clamp, acollar, a latch, a hook, adhesive, and/or other coupling devices. Thecentralizers may be configured to engage casing 12 at various locationsin well 8 to maintain a physical separation between tube 14 and casing12. The centralizers may include, for example, bow spring centralizers,floating collars, fixed position devices, mixed dielectric centralizers,and/or other centralizers. In some implementations, the centralizers maybe made from one or more conductive materials such as steel and/or othermaterials. In some implementations, the centralizers may be made fromnon-conductive materials.

Tube 14 may cooperate with casing 12 to form a coaxial transmissionline. One or more electrical loads (e.g., sensors 18) disposed withinwell 8 may be powered via the coaxial transmission line formed by casing12 and tube 14 without the need for electrical wiring. Casing 12 andtube 14 may be configured such that voltage and/or current across casing12 and tube 14 are sufficient to power the electrical load(s). In someimplementations, tube 14 may have a positive polarity and casing 12 mayhave a negative polarity. In some implementations, an electrical loadmay be electrically coupled with the electrically positive tube 14 andseparately with the electrically negative casing 12 such that the loadis powered via the connections.

Sensors 18 may be configured to generate output signals conveyinginformation related to the structural integrity of casing 12. The outputsignals may include output signals related to the casing-tubing pair.The information related to the structural integrity of casing 12 maycomprise information related to structural failures of casing 12,information related to potential structural failures of casing 12,and/or other information. The information related to structural failuresand/or the potential structural failures may include information relatedto movement of casing 12, tube 14, and/or other components of well 8.The information related to structural failures and/or the potentialstructural failures may include information related to physical defectsand/or a potential for physical defects in casing 12. The physicaldefects may include, for example, breaks, cracks, holes, deformations,loss of centralization, and/or other defects. Sensors 18 may compriseone or more sensors that measure such information directly (e.g.,through direct contact with casing 12). Sensors 18 may comprise one ormore sensors that generate output signals related to the structuralintegrity of casing 12 indirectly. For example, one or more of sensors18 may generate an output based on a characteristic of tube 14 (e.g., anamount of electrical current running through tube 14) and/or based on acharacteristic of the liquid and/or gas in tube 14 (e.g., a fluidlevel).

In some implementations, sensors 18 may include a single sensor type.Sensors 18 may include, for example, fluid level sensors, voltagesensors, acoustic sensors, pressure sensors, motion sensors, strainsensors, force sensors, flow sensors, composition sensors, temperaturesensors, strain gauges, accelerometers, and/or other sensors. Forexample, sensors 18 may include one or more strain gauges coupled withthe tube 14 and/or casing 12.

In some implementations, sensors 18 may include two or more differentsensor types. For example, fluid level sensors may generate outputsignals conveying information related to a fluid level in well 8. Insome implementations, the fluid level information may be indicative ofcasing 12 collapse, pressure in the casing, sheer forces acting on thecasing, an electrical short between tubing 14 and casing 12, an openbreach of the wall of casing 12, and/or other phenomena. A currentsensor (e.g., a transformer) on tube 14 may generate output signalsconveying information related to voltage and/or current changes in anotherwise closed circuit (e.g., due to movement, damage, etc.). Thiscould be multiplexed in more than one mode (sourced or passive). Thepassive mode may behave like a voltage and/or current receiver. Thevoltage and/or current sensors may be located just below a tubing hanger13. Hanger 13 may be configured to suspend the tube 14 in casing 12. Anacoustic sensor (e.g., an accelerometer and/or a microphone) may bemounted to tube 14, hanger 13, in and/or near wellhead 28, and/or atother locations. The spectral character of the monitored sound mayinclude mechanical motion and/or resonance information related to thestructural integrity of casing 12. One or more pressure sensors mountedin well 8 (e.g., in the annular space between tube 14 and casing 12,within tube 14, etc.) may convey information related to the pressure inthose areas of well 8, and/or the stability of those pressures. Forexample, an unstable pressure may indicate that a structural integrityevent has occurred and/or is about to occur. A motion sensor (e.g., anaccelerometer) may generate output signals related to movement of casing12, tube 14, and/or other components of well 8. Strain gages affixed totube 14 may generate output signals conveying information related tointernal stresses and/or strains.

Sensors 18 are illustrated in FIG. 1 and described above at variouslocations within system 10. In some implementations, at least one ofsensors 18 may be electrically coupled with tube 14 and casing 12separately. At least one of sensors 18 may be located in wellhead 28.Sensors 18 may be located at one or more locations along tube 14 withincasing 12. In some implementations, one or more of the sensors maycommunicate via tube 14. Sensors 18 may be located within casing 12 ator near tubing hanger 13 between wellhead 28 and tube 14.

For example, FIG. 2 illustrates a possible configuration of multiplesensors 18. A sensor assembly 200 may be packaged as a small “launcher”on a four foot sub 204. The sensors shown in FIG. 2 are examples of thesensors that may be included in such an assembly and are not intended tobe limiting. Assembly 200 may include other sensors not shown in FIG. 2.The sensors shown in FIG. 2 include a strain sensor 210 (e.g., a straingauge) and a current sensor 212. The current sensor may include, forexample, an RF/AC transformer coupled current monitor including amagnetic core on tube 14. Assembly 200 may be compactly located at ornear an underside 206 of tubing hanger 13. In some implementations,assembly 200 may include feed-thru capability in hanger 13 for wireleads 216. In some implementations, an acoustic transducer (not shown inFIG. 2) may be mounted on the top of hanger 13. In some implementations,the transducer may be thermally isolated. The collective electronics forassembly 200 may be packaged in a small enclosure. In someimplementations, sensor assembly 200 may be powered by a battery, solarpower, and/or other power sources/supplies. In some implementations,sensor assembly 200 may require a relatively low amount of power. Forexample, sensor assembly 200 may require about 5 to 10 watts. In someimplementations, sensor assembly 200 may include power management and RFsource generation circuitry not shown in FIG. 2.

Returning to FIG. 1, sensors 18 may include sensors disposed in aplurality of alternate locations in addition to and/or instead of thoseshown in FIG. 1. For example, sensors may be disposed within extractionequipment 16, and/or in other locations. In some implementations, tube14, casing 12, a conductive centralizer, and/or other components of well8 may be configured to provide a signal path for the output signals.

Processor 20 may be configured to provide information processingcapabilities in system 10. As such, processor 20 may include one or moreof a digital processor, an analog processor, a digital circuit designedto process information, an analog circuit designed to processinformation, a state machine, and/or other mechanisms for electronicallyprocessing information. Although processor 20 is shown in FIG. 1 as asingle entity, this is for illustrative purposes only. In someimplementations, processor 20 may include a plurality of processingunits. These processing units may be physically located within the samedevice, or processor 20 may represent processing functionality of aplurality of devices operating in coordination. Processor 20 may beconfigured to execute one or more computer program modules. Individualones the computer program modules may be configured to provide at leasta portion of the functionality attributed herein to processor 20.Processor 20 may be configured to execute the one or more computerprogram modules by software; hardware; firmware; some combination ofsoftware, hardware, and/or firmware; and/or other mechanisms forconfiguring processing capabilities on processor 20. It should beappreciated that the modules may be co-located within a singleprocessing unit, and/or one or more of the modules may be locatedremotely from the other modules. In some implementations, processor 20may be integrated with extraction equipment 16, user interface 22,and/or other components of system 10.

Processor 20 may be configured to detect casing structural integrityevents based on the output signals from sensors 18 and/or otherinformation. In some implementations, the casing structural integrityevents may include structural failures of the casing, potentialstructural failures of the casing, and/or other casing structure failureevents. The casing structural integrity events may be detectedresponsive to one or more forces acting on casing 12. The one or moreforces may include a shear force, a tensile force, a compressive force,a torsional force, and/or other forces. The one or more forces may begenerated by the geologic structure surrounding casing 12. For example,geologic layers and/or strata may shift on each other creating shearforces that act on casing 12. Processor 20 may be configured to generatecasing structural integrity event notifications that correspond to thedetected casing structural integrity events. The casing structuralintegrity event notifications may be generated for delivery to a userresponsive to the detections. Processor 20 may be configured to controluser interface 22 to display the notifications generated by processor20.

In some implementations, processor 20 may be configured to detect casingstructural integrity events based on the output signals from a singletype of sensors 18 (e.g., strain sensors). In some implementations,processor 20 may be configured to detect casing structural integrityevents based on the output signals from at two or more different typesof sensors 18. Processor 20 may be configured to process the informationconveyed by the output signals of the two or more different types ofsensors to detect casing structural integrity events. For example,processor 20 may be configured such that processing the informationincludes determining baseline well information, detecting casingstructural integrity events based on an algorithm, detecting casingstructural integrity events by clustering the information conveyed bythe output signals in a multidimensional space, determining a casingstructural integrity score and/or other metrics related to casingstructural integrity, determining well parameters, monitoring change inthe determined parameters (e.g., rate of change, standard deviation,and/or other measurements of change), determining well parameterthresholds, and/or other information processing. In someimplementations, processing the information may include determiningother information based on an integration and/or conglomeration of theinformation conveyed by the output signals.

In some implementations, determining baseline well information mayinclude determining information that indicates normal operation of well8. The information that indicates normal operation of well 8 may bedetermined by, for example, monitoring and evaluating multiple wellsduring various seasons of the year, at various production levels, and/orin various geographic locations. In some implementations, processor 20may be configured such that determining baseline well information mayinclude determining extraction parameters. The extraction parameters mayinclude information indicating whether the well is operating in aproduction phase, a pre-production phase, and/or other phases. Forexample, the extraction parameters may include parameters related towhether or not liquid and/or gas is actively flowing through tube 14. Insome implementations, the baseline well information for normal operationof well 8 during the pre-production may be different than during theproduction phase. Processor 20 may be configured to detect the casingstructural integrity events based on the extraction parameters. Forexample, processor 20 may be configured to determine that well 8 is in apre-production phase based on the extraction parameters. Processor 20may detect a casing structural integrity event responsive to theinformation conveyed by the output signals of sensors 18 being outsidethe normal well information range for the pre-production phase.

In some implementations, processor 20 may be configured to detect thecasing structural integrity events based on an algorithm. Processor 20may determine algorithm inputs based on the output signals. In someimplementations, processor 20 may be configured such that the algorithmmay be configured to indicate whether a casing structural integrityevent has occurred and/or will occur. The algorithm may be configured toindicate one or more structural integrity events occurring at one ormore locations in casing 12. Algorithm inputs may include informationconveyed by the output signals of sensors 18, baseline well informationdetermined by processor 20, one or more extraction parameters determinedby processor 20, one or more well parameters determined by processor 20,and/or other inputs. The one or more well parameters may include, forexample, a fluid level, a voltage, an acoustic parameter, a pressure, amotion parameter, a strain level, and/or other parameters. Algorithminputs may include currently determined information (e.g., the spectralcharacter of current well noise) and/or previously determinedinformation (e.g., the normal spectral character of well noise). In someimplementations, the algorithm may include and/or represent anelectronic model of well 8. In some implementations, the electronicmodel may be a mathematical model. The mathematical model may includemulti-dimensional model-based algorithms and/or other algorithmsconfigured to interpret the output signals generated by sensors 18.

By way of a non-limiting example, processor 20 may be configured todetermine a fluid level in well 8, a strain level in tube 14, and thespectral character of current noise in well 8 based on the outputsignals generated by three different types of sensors 18. The fluidlevel, the strain level, and the spectral character of the noise may bealgorithm inputs. Processor 20 may be configured such that the algorithmindicates that a structural integrity event is about to occur based onthe fluid level, the strain level, and the spectral character inputs. Inthis example, processor 20 may not have detected the structuralintegrity event based on the fluid level, the strain level, and or thespectral character of the noise alone. But as inputs to the algorithm,the fluid level, the strain level, and the spectral character of thenoise together indicated the structural integrity event. The three typesof information used in this example are not intended to be limiting. Thealgorithm may be configured to indicate structural integrity eventsbased on any amount and/or type of input.

In some implementations, the algorithm may include one or morealgorithms. The one or more algorithms may be determined at manufacture,programmed, adjusted, uploaded, and/or updated by a user via userinterface 22, and/or determined by other methods.

In some implementations, processor 20 may be configured to cluster theinformation conveyed by the output signals. Processor 20 may beconfigured to detect the casing structural integrity events based on theclustering. Clustering may comprise arranging the information conveyedby the output signals in a multidimensional space. Arranging theinformation in the multidimensional space may comprise grouping theinformation conveyed by the output signals of sensors 18 into separatedata clusters based on similarities in the information conveyed by theoutput signals. Similarities in the data may indicate, for example, thatwell 8 is operating normally. In some implementations, processor 20 maybe configured to cluster information conveyed by the output signals ofsensors 18 that indicates well 8 is operating normally into a first datacluster and information that indicates a casing structural integrityevent into one or more additional data clusters. The informationconveyed by the output signals of sensors 18 may be clustered byprocessor 20 based on statistical similarities in the information,magnitudes and/or directions of vectors that represent the informationin the multidimensional space, and/or other information. Clustering maybe known as networking in some implementations.

In some implementations, processor 20 may be configured to generatecasing structural integrity scores based on the output signals.Processor 20 may be configured to detect the casing structural integrityevents based on the casing structural integrity scores. In someimplementations, the casing structural integrity scores may beindividual values related to individual structural integrity events. Insome implementations, the casing structural integrity scores may beindividual values that indicate a likelihood that a structural integrityevent has occurred and/or will occur. In some implementations, processor20 may be configured such that the casing structural integrity scorescomprise weighted structural integrity scores. A weighted structuralintegrity score may comprise a collection of individually weightedscores based on information conveyed by the output signals fromindividual ones of the different types of sensors 18 (e.g., fluid level,strain, etc.) The individually weighted scores may be weighted based onindividual relationships between the information conveyed by the outputsignals from specific sensors 18 and whether that information has moreor less importance relative to a specific casing structural integrityevent. Processor 20 may be configured to determine the importance of theinformation conveyed by the output signals from specific sensors 18based on input from user interface 22, information determined atmanufacture, and/or other information.

In some implementations, processor 20 may be configured to determine oneor more well parameters based on the output signals. As described above,the one or more well parameters may include a fluid level, a voltage, anacoustic parameter, a pressure, a motion parameter, a strain level,and/or other parameters.

In some implementations, processor 20 may be configured to monitorchange in the determined parameters. Monitoring change may include,analyzing the determined parameters, comparing currently determinedparameters to previously determined parameters, generating one or moregraphics showing change in a given parameter over time, and/or othermonitoring. For example, processor 20 may be configured to analyze thedetermined parameters by determining a rate of change, a standarddeviation, a moving average, and/or other determinations representativeof change for a given parameter. Processor 20 may be configured togenerate a two dimensional graph showing a level of a given parameterover time. Change may be monitored based on various increments of time.Change may be monitored on a yearly basis, a monthly basis, a weeklybasis, a daily basis, an hourly basis, a minute by minute basis, asecond by second basis, and/or based on other increments of time. Forexample, a current pressure may be compared to a previous pressure thatwas determined one second prior to the current pressure. A currentamount of strain may be represented on a two dimensional graph withprior strain levels determined one day, one week, one month, and oneyear prior to the current strain level.

In some implementations, processor 20 may be configured to determinewell parameter threshold levels, and to detect the casing structuralintegrity events responsive to the well parameters breaching the wellparameter threshold levels. For example, a first casing structuralintegrity event may be detected responsive to a first well parameterbreaching a first well parameter threshold level. As a second example, asecond casing structural integrity event may be detected responsive tothe first well parameter breaching the first well parameter thresholdlevel and a second well parameter breaching a second well parameterthreshold level. Processor 20 may be configured to detect casingstructural integrity events based on any number well parametersbreaching any number of well parameter threshold levels. For example,processor 20 may detect a casing structural integrity event responsiveto six different well parameters breaching six corresponding wellparameter threshold levels. In some implementations, the well parameterthreshold levels may be determined at manufacture, programmed, adjusted,uploaded, and/or updated by a user via user interface 22, and/ordetermined by other methods.

User interface 22 may be configured to facilitate delivery of casingstructural integrity event notifications generated by processor 20and/or other information to users. User interface 22 may be configuredto receive entry and/or selection of information from users. Userinterface 22 may be configured to receive entry and/or selection ofcontrol inputs from users that facilitate operation of well 8 such thatthe users may adjust and/or cease the operation of well 8 if necessary,responsive to receiving casing structural integrity event notifications.Users may include well site managers, remote operators, petroleumengineers, and/or other users. This enables data, cues, results,notifications, instructions, and/or any other communicable items,collectively referred to as “information,” to be communicated betweenusers and processor 20, extraction equipment 16, and/or other componentsof system 10. Examples of interface devices suitable for inclusion inuser interface 22 comprise a keypad, buttons, switches, a keyboard,knobs, levers, a display screen, a touch screen, speakers, a microphone,an indicator light, an audible alarm, a printer, a tactile feedbackdevice, and/or other interface devices. In some implementations, userinterface 22 comprises a plurality of separate interfaces. In someimplementations, user interface 22 comprises at least one interface thatis provided integrally with processor 20 and/or extraction equipment 16.

It is to be understood that other communication techniques, eitherhard-wired or wireless, are also contemplated by the present disclosureas user interface 22. For example, the present disclosure contemplatesthat user interface 22 may be integrated with a removable electronicstorage interface disposed in extraction equipment 16. In this example,information may be loaded into system 10 from removable storage (e.g., asmart card, a flash drive, a removable disk, etc.) that enables theuser(s) to customize the implementation of system 10. Other exemplaryinput devices and techniques adapted for use with system 10 as userinterface 22 comprise, but are not limited to, an RS-232 port, RF link,an IR link, modem (telephone, cable or other). In short, any techniquefor communicating information with system 10 is contemplated by thepresent disclosure as user interface 22.

In some implementations, extraction equipment 16 may include equipmentconfigured to manage operation of well 8. Managing the operation of well8 may include drawing liquid and/or gas through well 8, storing theliquid and/or gas, monitoring well 8, powering well 8, preparing well 8for production, analyzing data related to the operation of well 8,and/or other activities. Such equipment may include pumps, piping,wiring, liquid and/or gas storage devices, power supplies, dataprocessing equipment (e.g., one or more computers and/or processors),communication equipment, cameras, safety systems, well control devices,and/or other extraction equipment. For example, a well power supply maybe configured to supply a positive polarity to tube 14 and a negativepolarity to casing 12. As another example, user interface 22 may beprovided by extraction equipment 16.

Wellhead 28 may be located at the surface of well 8. Wellhead 28 may beconfigured to suspend tube 14 and/or casing 12 in well 8. Wellhead 28may be a structural interface between tube 14 and extraction equipment16 configured to couple tube 14 with extraction equipment 16. Wellhead28 may be configured to contain pressure present in well 8. Wellhead 28may be configured to provide physical access to well 8 including accessto annular space(s) between casing 12 and/or tube 14. Wellhead 28 may beconfigured to provide electrical ports that are electrically coupledwith tube 14, casing 12, sensors 18, and/or other components of system10.

Extraction equipment 16, sensors 18, processor 20, user interface 22,and/or other components of system 10 may be operatively linked via oneor more electronic communication links. Such electronic communicationlinks may be wired and/or wireless. For example, such electroniccommunication links may be established, at least in part, via a networkand/or other links. In some implementations, extraction equipment 16,sensors 18, processor 20, and/or user interface 22, may be configured tocommunicate directly. It will be appreciated that this is not intendedto be limiting, and that the scope of this disclosure includesimplementations in which extraction equipment 16, sensors 18, processor20, user interface 22, and/or other components of system 10 may beoperatively linked via some other communication media, or with linkagesnot shown in FIG. 1.

FIG. 3 illustrates a natural resource field 300 that includes multiplewells 8. Sensors 18 and/or the other components of system 10 may belocated at the individual wells 8 and generate output signals conveyinginformation related to the structural integrity of the casings of theindividual wells 8 to processor 20. Such an arrangement of sensors 18and/or wells 8 in natural resource field 300 may facilitate mappinggeologic behavior of field 300. Geologic behavior may include, forexample, geologic movement, temperature changes, pressure changes,satellite provided geologic data, GPS data, and/or other geologicbehavior. In some implementations, the information generated for eachwell 8 may be time synchronized by processor 20 such that geologicevents may be detected and/or predicted in the areas of natural resourcefield 300 that are not directly instrumented. Notifications related tothe geologic behavior of natural resource field 300 may be generated byprocessor 20 for delivery to a user via user interface 22, for example.

FIG. 4 illustrates a method 400 for detecting structural integrity of awell casing in a well. The operations of method 400 presented below areintended to be illustrative. In some implementations, method 400 may beaccomplished with one or more additional operations not described,and/or without one or more of the operations discussed. Additionally,the order in which the operations of method 400 are illustrated in FIG.4 and described herein is not intended to be limiting.

In some implementations, method 400 may be implemented in one or moreprocessing devices (e.g., a digital processor, an analog processor, adigital circuit designed to process information, an analog circuitdesigned to process information, a state machine, and/or othermechanisms for electronically processing information). The one or moreprocessing devices may include one or more devices executing some or allof the operations of method 400 in response to instructions storedelectronically on one or more electronic storage mediums. The one ormore processing devices may include one or more devices configuredthrough hardware, firmware, and/or software to be specifically designedfor execution of one or more of the operations of method 400.

At an operation 402, conductive well tubing may be surrounded with aconductive well casing. The tubing may be configured to communicateliquid and/or gas from an underground reservoir to above groundextraction equipment at a wellhead. In some implementations, the tubingmay be a tubing string. The casing may be embedded in a geologicstructure. In some implementations, operation 402 may be performed by awell casing the same as or similar to casing 12 (shown in FIG. 1 anddescribed herein).

At an operation 404, output signals conveying information related to astructural integrity of the casing may be generated. The output signalsmay be generated with one or more sensors. In some implementations, theone or more sensors may include one or more sensor types. In someimplementations, the one or more sensors may include two or more sensortypes. The sensor types may include fluid level sensors, voltagesensors, acoustic sensors, pressure sensors, motion sensors, strainsensors, and/or other sensors. The sensors may be located at variouslocations in and/or near the well. At least one of the sensors may beelectrically coupled with the well tubing and the well casingseparately. At least one of the sensors may be located in the wellhead.The one or more sensors may be located at one or more locations alongthe tubing within the casing. The one or more sensors may be locatedwithin the well casing at or near a tubing hanger between the wellheadand the well tubing. The tubing hanger may be configured to suspend thetubing in the casing. In some implementations, operation 404 may beperformed by sensors the same as or similar to sensors 18 (shown in FIG.1 and described herein).

At an operation 406, casing structural integrity events may be detected.The casing structural integrity events may be detected based on theoutput signals. The casing structural integrity events may be detectedresponsive to one or more forces acting on the well casing. The one ormore forces may include a shear force, a tensile force, and acompressive force, a torsional force, and/or other forces. The one ormore forces may be generated by the geologic structure surrounding thecasing.

In some implementations, extraction parameters may be determined atoperation 406. The extraction parameters may be determined based on theoutput signals and/or other information. Detecting the well casingstructural integrity events may be based on the extraction parameters.The extraction parameters may include information indicating whether thewell is operating in a production phase or a pre-production phase. Insome implementations, the casing structural integrity events may bedetected based on an algorithm. The algorithm inputs may be determinedbased on the output signals. In some implementations, at operation 406,the information conveyed by the output signals may be clustered and/ornetworked. Detecting the casing structural integrity events may be,based on the clustering. Clustering may comprise arranging theinformation conveyed by the output signals in a multidimensional space.In some implementations, at operation 406, casing structural integrityscores may be generated based on the output signals. Detecting thecasing structural integrity events may be based on the casing structuralintegrity scores. In some implementations, at operation 406, one or morewell parameters may be determined based on the output signals. The oneor more well parameters may include one or more of a fluid level, avoltage, an acoustic parameter, a pressure, a motion parameter, a strainlevel, and/or other parameters. Well parameter threshold levels may bedetermined and the casing structural integrity events may be detectedresponsive to the well parameters breaching the well parameter thresholdlevels. For example, a first casing structural integrity event may bedetected responsive to a first well parameter breaching a first wellparameter threshold level.

In some implementations, operation 406 may be performed by a processorthe same as or similar to processor 20 (shown in FIG. 1 and describedherein).

At an operation 408, casing structural integrity event notificationsthat correspond to the detected casing structural integrity events maybe generated. The notifications may be generated for delivery to a userresponsive to the detections. The well casing structural integrityevents may include one or both of structural failures of the casingand/or potential structural failures of the casing. In someimplementations, operation 408 may be performed by a processor the sameas or similar to processor 20 (shown in FIG. 1 and described herein).

Although the present technology has been described in detail for thepurpose of illustration based on what is currently considered to be themost practical and preferred implementations, it is to be understoodthat such detail is solely for that purpose and that the technology isnot limited to the disclosed implementations, but, on the contrary, isintended to cover modifications and equivalent arrangements that arewithin the spirit and scope of the appended claims. For example, it isto be understood that the present technology contemplates that, to theextent possible, one or more features of any implementation can becombined with one or more features of any other implementation.

1. A system configured to detect structural integrity of a well casingin a well, the system comprising: a conductive well casing configured tosurround conductive well tubing, the tubing being configured tocommunicate liquid and/or gas from an underground reservoir to aboveground extraction equipment at or near a wellhead, the casing beingembedded in a geologic structure; one or more sensors configured togenerate output signals conveying information related to a structuralintegrity of the casing and/or a casing-tubing pair, and one or moreprocessors configured to detect casing structural integrity events basedon the output signals, and to generate casing structural integrity eventnotifications that correspond to the detected casing structuralintegrity events for delivery to a user responsive to the detections,the casing structural integrity events including one or both ofstructural failures of the casing or potential structural failures ofthe casing.
 2. The system of claim 1, wherein the one or more processorsare further configured to determine extraction parameters and to detectthe casing structural integrity events based on the extractionparameters, the extraction parameters including information indicatingwhether the well is operating in a production phase or a pre-productionphase.
 3. The system of claim 1, wherein the one or more processors areconfigured to detect the casing structural integrity events based on analgorithm, wherein the one or more processors determine algorithm inputsbased on the output signals.
 4. The system of claim 1, wherein the oneor more sensors include one or more sensor types, the one or moresensors including fluid level sensors, voltage sensors, acousticsensors, pressure sensors, motion sensors, current sensors, and strainsensors.
 5. The system of claim 1, wherein the one or more sensorsinclude two or more sensor types, the one or more sensors includingfluid level sensors, voltage sensors, current sensors, acoustic sensors,pressure sensors, motion sensors, and strain sensors.
 6. The system ofclaim 1, wherein the one or more processors are configured such that thecasing structural integrity events are detected responsive to one ormore forces acting on the casing, the one or more forces including ashear force, a tensile force, a compressive force, and a torsionalforce, the one or more forces generated by the geologic structuresurrounding the casing.
 7. The system of claim 1, wherein the one ormore processors are configured to cluster the information conveyed bythe output signals and detect the casing structural integrity eventsbased on the clustering, wherein clustering includes networking and/orarranging the information conveyed by the output signals in amultidimensional space.
 8. The system of claim 1, where the one or moreprocessors are configured to generate casing structural integrity scoresbased on the output signals, and detect the casing structural integrityevents based on the casing structural integrity scores.
 9. The system ofclaim 1, wherein the one or more processors are further configured todetermine one or more well parameters based on the output signals, theone or more well parameters including one or more of a fluid level, avoltage, a current, an acoustic parameter, a pressure, a motionparameter, or a strain level, wherein the one or more processors areconfigured to determine well parameter threshold levels, and wherein theone or more processors are configured to detect the casing structuralintegrity events responsive to the well parameters breaching the wellparameter threshold levels such that a first casing structural integrityevent is detected responsive to a first well parameter breaching a firstwell parameter threshold level.
 10. The system of claim 1, wherein atleast one of the one or more sensors is electrically coupled with thetubing and the casing separately.
 11. The system of claim 1, wherein atleast one of the one or more sensors is located in the wellhead.
 12. Thesystem of claim 1, wherein the one or more sensors are located at one ormore locations along the tubing within the casing.
 13. The system ofclaim 1, wherein the one or more sensors are located within the casingat or near a tubing hanger between the wellhead and the tubing, thetubing hanger being configured to suspend the tubing in the casing. 14.A method for detecting structural integrity of a well casing in a well,the method comprising: surrounding conductive well tubing with aconductive well casing, the tubing being configured to communicateliquid and/or gas from an underground reservoir to above groundextraction equipment at a wellhead, the casing being embedded in ageologic structure; generating output signals conveying informationrelated to a structural integrity of the casing; detecting casingstructural integrity events based on the output signals, and generatingcasing structural integrity event notifications that correspond to thedetected casing structural integrity events for delivery to a userresponsive to the detections, the casing structural integrity eventsincluding one or both of structural failures of the casing or potentialstructural failures of the casing.
 15. The method of claim 14, furthercomprising determining extraction parameters and detecting the casingstructural integrity events based on the extraction parameters, theextraction parameters including information indicating whether the wellis operating in a production phase or a pre-production phase.
 16. Themethod of claim 14, further comprising detecting the casing structuralintegrity events based on an algorithm, wherein the algorithm inputs aredetermined based on the output signals.
 17. The method of claim 14,further comprising generating the output signals with one or moresensors, the one or more sensors including one or more sensor types, theone or more sensors including fluid level sensors, voltage sensors,current sensors, acoustic sensors, pressure sensors, motion sensors, andstrain sensors.
 18. The method of claim 14, further comprisinggenerating the output signals with one or more sensors, wherein the oneor more sensors include two or more sensor types, the one or moresensors including fluid level sensors, voltage sensors, acousticsensors, pressure sensors, motion sensors, and strain sensors.
 19. Themethod of claim 14, wherein the casing structural integrity events aredetected responsive to one or more forces acting on the casing, the oneor more forces including a shear force, a torsional force, a tensileforce, and a compressive force, the one or more forces generated by thegeologic structure surrounding the casing.
 20. The method of claim 14,further comprising clustering the information conveyed by the outputsignals and detecting the casing structural integrity events based onthe clustering, wherein clustering comprises arranging the informationconveyed by the output signals in a multidimensional space.
 21. Themethod of claim 14, further comprising generating casing structuralintegrity scores based on the output signals, and detecting the casingstructural integrity events based on the casing structural integrityscores.
 22. The method of claim 14, further comprising determining oneor more well parameters based on the output signals, the one or morewell parameters including one or more of a fluid level, a voltage, anacoustic parameter, a pressure, a motion parameter, or a strain level,determining well parameter threshold levels, and detecting the casingstructural integrity events responsive to the well parameters breachingthe well parameter threshold levels such that a first casing structuralintegrity event is detected responsive to a first well parameterbreaching a first well parameter threshold level.
 23. The method ofclaim 14, further comprising generating the output signals with one ormore sensors, and electrically coupling at least one of the one or moresensors with the tubing and the casing separately.
 24. The method ofclaim 14, further comprising generating the output signals with one ormore sensors, wherein at least one of the one or more sensors is locatedin the wellhead.
 25. The method of claim 14, further comprisinggenerating the output signals with one or more sensors, wherein the oneor more sensors are located at one or more locations along the tubingwithin the casing.
 26. The method of claim 14, further comprisinggenerating the output signals with one or more sensors, wherein the oneor more sensors are located within the casing at or near a tubing hangerbetween the wellhead and the tubing, the tubing hanger being configuredto suspend the tubing in the casing.